Diffusion and melting of adsorbed monolayers by Mössbauer spectroscopy
نویسنده
چکیده
2014 Mössbauer spectroscopy is applied to the study of dynamical properties of adsorbed monolayers with special attention to changes in resonant absorption cross section caused by diffusion along the surface. Specific systems studied were films of butadiene iron tricarbonyl on exfoliated graphite (Papyex) at several coverages, from 130 K to room temperature. The absorption spectra of the Fe57 constituent were measured in the direction parallel to the average film plane and normal to it. In the parallel direction, the temperature dependence of absorption is normal at low temperature, but decreases abruptly to undetectable levels near 150 K, indicating first order phase changes to a fluid phase. The results are analysed in terms of a detailed theory of diffusive broadening in surface films. Effects of crystallite orientation are treated, with specific reference to the partial alignment in Papyex and Grafoil. LE JOURNAL DE PHYSIQUE TOME 40, MAI 1979,
منابع مشابه
Quasielastic neutron scattering and molecular dynamics simulation studies of the melting transition in butane and hexane monolayers adsorbed on graphite
Quasielastic neutron scattering experiments and molecular dynamics ~MD! simulations have been used to investigate molecular diffusive motion near the melting transition of monolayers of flexible rod-shaped molecules. The experiments were conducted on butane and hexane monolayers adsorbed on an exfoliated graphite substrate. For butane, quasielastic scattering broader than the experimental energ...
متن کاملOrientational order in xenon fluid monolayers on single crystals of exfoliated graphite.
The melting transition of Xe monolayers adsorbed on a single-crystal exfoliated graphite substrate has been studied by high-resolution synchrotron x-ray scattering. At temperatures slightly above the melting transition the fluid phase has a high degree of orientational order. The results are discussed in the context of current theories of two-dimensional melting including the effects of the sub...
متن کاملBehenic Acid Monolayer and Bilayer Assemblies- A Study of Concanavalin A (Con A) Adsorption and its Interaction with Dextran Using Surface Plasmon Resonance Spectroscopy and Microscopy
Deposition of behenic acid (B.A) mono and bilayers onto gold coated surfaces was performed by Langmuir-Blodget dip-casting technique. Surface Plasmon resonance (SPR) and ellipsometry methods were employed for investigation of the monolayer and bilayer films. The adsorption of the biologically important molecule Concanavalin A (Con A) from bulk solution to these monolayers and bilayers as we...
متن کاملMolecular dynamics studies of the melting of butane and hexane monolayers adsorbed on the basal-plane surface of graphite
متن کامل
Structure and Thermodynamics of Self-Assembled Monolayers on Gold Nanocrystallites
Equilibrium structures and thermodynamic properties of dodecanethiol self-assembled monolayers on small (Au140) and larger (Au1289) gold nanocrystallites were investigated with the use of molecular dynamics simulations. Compact passivating monolayers are formed on the (111) and (100) facets of the nanocrystallites, with adsorption site geometries differing from those found on extended flat Au(1...
متن کامل